Concept

Groupe affine

Publications associées (72)

On the fundamental domain of affine Springer fibers

Let G be a connected reductive algebraic group over an algebraically closed field k,gamma is an element of g( k(( epsilon ))) a semisimple regular element, we introduce a fundamental domain F gamma for the affine Springer fibers X gamma. We show that the p ...

Springer Heidelberg2017

The tropical momentum map: a classification of toric log symplectic manifolds

Tudor Ratiu

We give a generalization of toric symplectic geometry to Poisson manifolds which are symplectic away from a collection of hypersurfaces forming a normal crossing configuration. We introduce the tropical momentum map, which takes values in a generalization ...

Springer Verlag2017

An upper bound for the Tarski numbers of nonamenable groups of piecewise projective homeomorphisms

Yash Lodha

The Tarski number of a nonamenable group is the smallest number of pieces needed for a paradoxical decomposition of the group. Nonamenable groups of piecewise projective homeomorphisms were introduced in [N. Monod, Groups of piecewise projective homeomorph ...

World Scientific Publ Co Pte Ltd2017

The Geometric Nature of the Flaschka Transformation

Tudor Ratiu, François Gay-Balmaz

We show that the Flaschka map, originally introduced to analyze the dynamics of the integrable Toda lattice system, is the inverse of a momentum map. We discuss the geometrical setting of the map and apply it to the generalized Toda lattice systems on semi ...

Springer Verlag2017

Notions of affinity in calculus of variations with differential forms

Saugata Bandyopadhyay, Swarnendu Sil

Ext-int. one affine functions are functions affine in the direction of one-divisible exterior forms with respect to the exterior product in one variable and with respect to the interior product in the other. The purpose of this article is to prove a charac ...

Walter De Gruyter Gmbh2016

Enumeration of reversible functions and its application to circuit complexity

Giovanni De Micheli, Mathias Soeken, Nabila Abdessaied

We review combinational results to enumerate and classify reversible functions and investigate the application to circuit complexity. In particularly, we consider the effect of negating and permuting input and output variables and the effect of applying li ...

Springer2016

Hermite Snakes with Control of Tangents

Michaël Unser, Julien René Pierre Fageot, Virginie Sophie Uhlmann

We introduce a new model of parametric contours defined in a continuous fashion. Our curve model relies on Hermite spline interpolation and can easily generate curves with sharp discontinuities; it also grants direct access to the tangent at each location. ...

IEEE2016

MATHICSE Technical Report : Multiscale methods and model order reduction for flow problems in three-scale porous media

Assyr Abdulle, Ondrej Budác

A new multiscale method combined with model order reduction is proposed for flow problems in three-scale porous media. We derive an effective three-scale model that couples a macroscopic Darcy equation, a mesoscopic Stokes-Brinkman equation, and a microsco ...

MATHICSE2016

Homology of the three flag Hilbert Scheme

Daniele Boccalini

We prove the existence of an affine paving for the three-step flag Hilbert scheme that parametrizes flag of three 0-dimensional subschemes of length, respectively, n, n+1 and n+2 that are supported at the origin of the affine plane. This is done by showing ...

EPFL2016

Efficient Shape Priors for Spline-Based Snakes

Michaël Unser, Daniel Andreas Schmitter, Ricard Delgado Gonzalo, Virginie Sophie Uhlmann

Parametric active contours are an attractive approach for image segmentation, thanks to their computational efficiency. They are driven by application-dependent energies that reflect the prior knowledge on the object to be segmented. We propose an energy i ...

2015

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